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Seal is not enough--why boiling is

veeta
10 years ago

Just curious if I have a correct understanding. The reason you boil, say jam for example, for the recommended time is to kill anything that may be present in the jar as well as ensure a tight seal. Some people are under the impression that just getting a premature "ping" seal is sufficient. Do I have it right?

Comments (15)

  • readinglady
    10 years ago

    If you are speaking of a full-sugar "traditional" jam made from high-acid fruit, strictly speaking it wouldn't be necessary to do anything other than open-kettle, i.e. pour the hot preserve into sterile jars and cover with paraffin or the wax paper disks common in Europe or slap a lid and ring on it American-style and call it good.

    Water processing improves shelf life and long-term quality because you don't risk the waste of mold and with a stronger vacuum there's little air in the jar to cause deterioration.

    But even unprocessed jams of the sort I'm speaking of present no health risk (unless you choose to eat moldy product).

    Carol

  • NilaJones
    10 years ago

    Yes. There is guaranteed to be 'stuff' present in the jar, no matter how squeaky clean and sterilised -- mold spores, bacteria, etc.

    Jam will ferment if it does not have a ton of sugar, and probably get moldy even if it does, unless you can it (boil in when it's inside the jars with lids). It won't really hurt you, but is gross and might make you ill.

    Meat and vegetables will kill you.

    I now await answers from folks who know more than I :).

  • NilaJones
    10 years ago

    Yes, old-fashioned jam and jelly recipes with lots and lots of sugar are ok (you might have to scrape off the mold).

    But I think most folks nowdays make their jam with less sugar. And then it does ferment.

  • readinglady
    10 years ago

    It's no longer recommended to scrape off mold and eat the remainder because mold filaments extend into the preserve far below the visible level. So far studies have not shown mold causes cancer but there is a correlation between mold and cancer. Further studies may definitely resolve that question.

    Carol

  • digdirt2
    10 years ago

    The reason you boil, say jam for example, for the recommended time is to kill anything that may be present in the jar as well as ensure a tight seal.

    Re-worded: The reason you boiling water bath jams/jellies for the recommended time (usually 10 min.) is to kill anything that may be present in the jar or in the ingredients as well as to ensure a full vacuum inside the jar and a tight seal.

    Some people are under the impression that just getting a premature "ping" seal is sufficient.

    It is only a temporary seal, easily lost. And it is not a full vacuum inside the jar as air remains trapped in there. Trapped air encourages the growth of any molds, bacteria, and fungi present.

    Some studies I have read indicate that as much as 40% of the jars that are not properly BWB processed are lost to contamination and so wasted.

    Dave

  • NilaJones
    10 years ago

    >So far studies have not shown mold causes cancer but there is a correlation between mold and cancer.

    Oh my goodness, I didn't know that! Does it apply to cheese with intentional mold culture?

  • readinglady
    10 years ago

    No, those are entirely different strains of mold. You can eat your blue cheese with no worries whatsoever.

    Not all molds are harmful (think penicillin).

    40%! I can't imagine that. We canned all kinds of jams and jellies open-kettle and paraffin sealed or two-piece lid sealed when I was a child.

    While I'm sure we must have lost a jar somewhere along the way I don't remember it as any sort of common occurrence. It seems to me that would be far more likely with low-sugar formulations.

    Carol

  • NilaJones
    10 years ago

    Thank you, Carol, about the mold :).

    Yes, 40% seems crazy to me, too, for high-sugar stuff. I have, personally, had jam with less sugar ferment. And it IS sad! Taught me to process it like unsweetened fruit :).

  • seysonn
    10 years ago

    Wort come to worst, you can reboil the stuff. Though most molds are not harmful to the point of being poisonous. I Eat bread with mold on it all the time. Just toast it. I love BLUE CHEESE too . hehe

  • digdirt2
    10 years ago

    Wort come to worst, you can reboil the stuff.

    Sure but then you won't have jam or jelly but moldy syrup instead as it would break the set. Boiling does not kill all molds unless you want to do it for 30 mins. or 15 mins under pressure.

    And some food molds can make you quite ill - mycotoxins and aflotoxins specifically.

    Dave

    Here is a link that might be useful: USDA - Food Molds

  • readinglady
    10 years ago

    Boiled or not moldy jam is still moldy. Not only that but it would taste moldy.

    Carol

  • Linda_Lou
    10 years ago

    Some molds, as we are taught and also teach in our food preservation classes, do contain mycotoxins that cause some cancers and can also cause some forms of arthritis. They are not harmless. Eating moldy bread is also not safe. The mold you see is just the tip of the iceberg. It is like a plant, the mold you see is like the flower. The rest is roots, that you don't see. It is FULL of mold.
    Not something a person who values their health will eat.

    Here is a link that might be useful: Mold on foods

  • calliope
    10 years ago

    My mother always used paraffin on her jams and jellies. I began processing mine when a lot of folks still used paraffin. I liked to give mine as gifts and sometimes sent jars by post and that means they needed a great seal. When I did use paraffin, I didn't have 40% loss, but it was almost an art to putting the paraffin in, too much and it pulled away from the jar. Not enough and a piece of fruit might poke through when the wax cooled and shrank. I am a candlemaker, however and have a feel for how paraffin acts when heated and cooled, and I still lost a few jars. Much too easy to just process it to mess with anything else.

  • readinglady
    10 years ago

    In my family we thanked our lucky stars when two-piece lids replaced paraffin. I do know some who use it for gifts because it makes using non-standard canning jars possible, but for myself it's just a messy unreliable process. Not only that, but a lot of people have difficulty removing the paraffin. That seems as much a lost art as applying.

    Carol

  • calliope
    10 years ago

    Exactly, and I have pulled more pieces of wax off my bread than I can to think about, and probably ate even more of it.